All diagrams in synapses and receptor signalling
Glutamate glutamine cellular shuttle
The glutamate–glutamine shuttle links neurons and astrocytes. Astrocytic amino-acid recycling is not synaptic-vesicle membrane recycling.
Glutamate glutamine cellular shuttle
Scoped educational mechanism
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Neurons import glutamine and use mitochondrial glutaminase to form glutamate, which is available for vesicular transport and release after cytosolic transfer. Astrocytic uptake and cytosolic glutamine synthetase support glutamine regeneration, followed by transport back to neurons. GABA-producing neurons can use glutamate as precursor, but that additional branch is not the same as the glutamatergic vesicle cycle. The schematic omits some membrane/transport intermediates and does not assert a defect in a particular reader.
- Neuron: glutamine → Neuron: GLS: GLS
- Neuron: GLS → Neuron: release: loading / release
- Neuron: release → Astrocyte: uptake: EAAT
- Astrocyte: uptake → Astrocyte: GLUL: GLUL
- Astrocyte: GLUL → Glutamine export: export
- Glutamine export → Neuron: glutamine: uptake
What the diagram shows
Neurons import glutamine and use mitochondrial glutaminase to form glutamate, which is available for vesicular transport and release after cytosolic transfer. Astrocytic uptake and cytosolic glutamine synthetase support glutamine regeneration, followed by transport back to neurons. GABA-producing neurons can use glutamate as precursor, but that additional branch is not the same as the glutamatergic vesicle cycle. The schematic omits some membrane/transport intermediates and does not assert a defect in a particular reader.